Theoretical study of fundamental processes of quantum electrodynamics (QED) in strong laser fields (see, for example, articles [1]}, [2]}, [3]}, [4]}, [5]}, [6]}, [7]}, [8]}, [9]}, [10]}, [11]}, [12]}, [13]}, [14]}, [15]}, [16]}, [17]}, [18]}, [19]}, [20]}, [21]}, [22]}, [23]}, [24]}, [25]}, [26]}, [27]}, [28]}, [29]}, [30]}, [31]}, [32]}, [33]}, [34]}, reviews [35]}, [36]}, [37]}, [38]}, [39]}, [40]} and monographs [41]}, [42]}, [43]}, [44]}) is connected not only with the development of QED, but also with the creation of powerful laser radiation sources [45]}, [46]}, [47]}, [48]}, [49]}. It is important to emphasize that higher-order QED processes with respect to the fine structure constant in a laser field can proceed both in a resonant and non-resonant way. Here, the so-called Oleinik resonances may occur [2]}, [3]}, due to the fact that lower-order processes are allowed in the laser field by the fine structure constant. It is important to note that the resonant differential cross-section can significantly exceed the corresponding non-resonant one [36]}, [37]}, [38]}, [39]}, [40]}.
